This invention relates to a method and apparatus for binding sheets of paper inside a cover, and, more particularly, to a permanent binding utilizing a heat-reactivatible adhesive.
My copending application, U.S. Serial 658,336, now U.S. Pat. No. 3,995,886 describes a binding method wherein a quantity of heat-reactivatible adhesive is applied to the inside of a cover near the junction point of the leaves. A plurality of sheets are then placed into the cover such that ends of the sheets are near the junction of the leaves. The apparatus is then subjected to an oscillatory motion and heat which causes the molten adhesive to flow and intimately engage the ends of the sheets. Upon cooling, the assembly forms a bound book. Such a bound book or binding method is particularly suitable for a plurality of sheets whose thickness is greater than approximately one-eighth inch. With bound books having a final thickness of less than one-eighth inch, the process is less efficient and some of the pages may not be engaged by the molten adhesive.
A disadvantage with prior art binding methods for loose sheets is the need to introduce mounting holes into the cover and the paper sheets. Also, binding methods such as spiral wire or plastic loops must be carefully threaded through the cover and paper sheets, resulting in low production time and expensive machinery.